Roof trusses have changed quite a bit throughout the years with a variety of designs over many decades. - http://www.timberlaketrussworks.com/

1. THE HISTORY/EVOLUTION
OF ROOF TRUSSES

2. ROOF TRUSSES HAVE CHANGED QUITE A BIT
THROUGHOUT THE YEARS WITH A VARIETY
OF DESIGNS OVER MANY DECADES.

3. TRUSS CONSTRUCTION HAS LONG BEEN
ASSOCIATED WITH HIGH-END
VERNACULAR CARPENTRY.

4. THE TRUSS FORM ORIGINALLY CAME OUT
FROM THE TIMBER FRAMING METHODS OF
CLASSICAL ANTIQUITY IN THE MEDITERRANEAN REGION.

5. FROM THE MIDDLE AGES THROUGH THE RENAISSANCE,
THERE WERE A VARIETY OF LONG-SPAN ROOF SYSTEMS
USED IN BUILDING DIFFERENT STRUCTURES.

6. EXCEPT FOR THE PANTHEON IN ROME,
ALL ANCIENT TRUSS MEMBERS WERE MADE OUT
OF WOOD FOR NEARLY TWO MILLENNIA

7. UNTIL IRON AND STEEL ROOF FRAMES
STARTED BEING MADE AT THE END
OF THE 18TH CENTURY.

8. METAL WAS USED IN TRUSSES
DATING BACK TO THE MIDDLE AGES,
THOUGH INCONSISTENTLY.

9. WROUGHT IRON STRAPS WITH FORELOCK BOLTS
WERE USED TO REINFORCE TENSION JOINERY.

10. NEOCLASSICAL ARCHITECTURE FOR LARGE HALLS,
ESPECIALLY IN THE AMERICAN
POST-REVOLUTIONARY PERIOD

11. HAD A BIG INFLUENCE
OF THE SIMPLIFICATION OF TRUSS DESIGN.

12. SIMPLIFICATION OF TRUSS DESIGN
ALSO CAME ABOUT FROM THE AVAILABILITY
OF LARGE, LONG TIMBER,

13. AS WELL AS THE RISING POPULARITY OF LONG-SPAN
WOOD TRUSS BRIDGE CONSTRUCTION AND NEW
TECHNOLOGY IN LATE 18TH CENTURY NORTH AMERICA.

14. TODAY, WOOD TRUSSES ARE STILL COMMONLY USED
TO BUILD A MULTITUDE OF STRUCTURES, INCLUDING
CHURCHES, BRIDGES, AND EVEN PRIVATE HOMES.